<html>
  <script type="module" src="popup.js"></script>
  <style>
    iframe {
      border: none;
    }
  </style>
  <body>
    <div>
      <button type="button" id="mainPageButton">Settings</button>
    </div>
    <iframe src="co2-state-iframe.html"></iframe>
  </body>
</html>
